From 65966e0c3da0fdb5a59abcc76533dfceccbc1425 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Sat, 25 Feb 2023 08:59:03 -0700
Subject: [PATCH] [wasm-api] Add font_copy_glyph_outline

---
 src/hb-wasm-api-font.hh             | 46 +++++++++++++++++++++++++++++
 src/hb-wasm-api-list.hh             |  1 +
 src/hb-wasm-api.h                   | 36 ++++++++++++++++++++--
 src/wasm/sample/c/shape-fallback.cc |  4 +++
 4 files changed, 85 insertions(+), 2 deletions(-)

diff --git a/src/hb-wasm-api-font.hh b/src/hb-wasm-api-font.hh
index e3e5453d7..d1401c7e0 100644
--- a/src/hb-wasm-api-font.hh
+++ b/src/hb-wasm-api-font.hh
@@ -27,6 +27,8 @@
 
 #include "hb-wasm-api.hh"
 
+#include "hb-outline.hh"
+
 namespace hb {
 namespace wasm {
 
@@ -109,6 +111,50 @@ HB_WASM_API (void, font_glyph_to_string) (HB_WASM_EXEC_ENV
   hb_font_glyph_to_string (font, glyph, s, size);
 }
 
+static_assert (sizeof (glyph_outline_point_t) == sizeof (hb_outline_point_t), "");
+static_assert (sizeof (uint32_t) == sizeof (hb_outline_t::contours[0]), "");
+
+HB_WASM_API (bool_t, font_copy_glyph_outline) (HB_WASM_EXEC_ENV
+					       ptr_d(font_t, font),
+					       codepoint_t glyph,
+					       ptr_d(glyph_outline_t, outline))
+{
+  HB_REF2OBJ (font);
+  HB_PTR_PARAM (glyph_outline_t, outline);
+  if (unlikely (!outline))
+    return false;
+
+  hb_outline_t hb_outline;
+  auto *funcs = hb_outline_recording_pen_get_funcs ();
+
+  hb_font_draw_glyph (font, glyph, funcs, &hb_outline);
+
+  if (unlikely (hb_outline.points.in_error () ||
+		hb_outline.contours.in_error ()))
+  {
+    outline->n_points = outline->n_contours = 0;
+    return false;
+  }
+
+  outline->n_points = hb_outline.points.length;
+  outline->points = wasm_runtime_module_dup_data (module_inst,
+						  (const char *) hb_outline.points.arrayZ,
+						  hb_outline.points.get_size ());
+  outline->n_contours = hb_outline.contours.length;
+  outline->contours = wasm_runtime_module_dup_data (module_inst,
+						    (const char *) hb_outline.contours.arrayZ,
+						    hb_outline.contours.get_size ());
+
+  if ((outline->n_points && !outline->points) ||
+      (!outline->n_contours && !outline->contours))
+  {
+    outline->n_points = outline->n_contours = 0;
+    return false;
+  }
+
+  return true;
+}
+
 
 }}
 
diff --git a/src/hb-wasm-api-list.hh b/src/hb-wasm-api-list.hh
index 545b2f098..4e5172450 100644
--- a/src/hb-wasm-api-list.hh
+++ b/src/hb-wasm-api-list.hh
@@ -78,6 +78,7 @@ static NativeSymbol _hb_wasm_native_symbols[] =
   NATIVE_SYMBOL ("(ii)i",	font_get_glyph_v_advance),
   NATIVE_SYMBOL ("(iii)i",	font_get_glyph_extents),
   NATIVE_SYMBOL ("(ii$*)",	font_glyph_to_string),
+  NATIVE_SYMBOL ("(iii)i",	font_copy_glyph_outline),
 
   /* shape */
   NATIVE_SYMBOL ("(iiii$)i",	shape_with),
diff --git a/src/hb-wasm-api.h b/src/hb-wasm-api.h
index 43327cd35..5600d431b 100644
--- a/src/hb-wasm-api.h
+++ b/src/hb-wasm-api.h
@@ -207,7 +207,8 @@ HB_WASM_API (position_t, font_get_glyph_v_advance) (HB_WASM_EXEC_ENV
 						    ptr_d(font_t, font),
 						    codepoint_t glyph);
 
-typedef struct {
+typedef struct
+{
   position_t x_bearing;
   position_t y_bearing;
   position_t width;
@@ -225,9 +226,40 @@ HB_WASM_API (void, font_glyph_to_string) (HB_WASM_EXEC_ENV
 					  char *s, uint32_t size);
 
 
+/* outline */
+
+enum glyph_outline_point_type_t
+{
+  MOVE_TO,
+  LINE_TO,
+  QUADRATIC_TO,
+  CUBIC_TO,
+};
+
+typedef struct
+{
+  float x;
+  float y;
+  uint32_t type;
+} glyph_outline_point_t;
+
+typedef struct
+{
+  uint32_t n_points;
+  ptr_t(glyph_outline_point_t) points;
+  uint32_t n_contours;
+  ptr_t(uint32_t) contours;
+} glyph_outline_t;
+
+HB_WASM_API (bool_t, font_copy_glyph_outline) (HB_WASM_EXEC_ENV
+					       ptr_d(font_t, font),
+					       codepoint_t glyph,
+					       ptr_d(glyph_outline_t, outline));
+
 /* shape */
 
-typedef struct {
+typedef struct
+{
   tag_t    tag;
   uint32_t value;
   uint32_t start;
diff --git a/src/wasm/sample/c/shape-fallback.cc b/src/wasm/sample/c/shape-fallback.cc
index 85834a1c1..335331c2c 100644
--- a/src/wasm/sample/c/shape-fallback.cc
+++ b/src/wasm/sample/c/shape-fallback.cc
@@ -42,6 +42,10 @@ shape (void *shape_plan,
 
     contents.info[i].codepoint = font_get_glyph (font, contents.info[i].codepoint, 0);
     contents.pos[i].x_advance = font_get_glyph_h_advance (font, contents.info[i].codepoint);
+
+    glyph_outline_t outline;
+    font_copy_glyph_outline (font, contents.info[i].codepoint, &outline);
+    debugprint1 ("num outline contours", outline.n_contours);
   }
 
   bool_t ret = buffer_set_contents (buffer, &contents);